| Abstract: | Dillerent chicken tissues are shown to display a clearly pronounced specificity relative to 2-14C] orotic acid and 5-3H]uridine as precursors of synthesis of the pool and RNA pyrimidine nucleotides. The fraction of pyrimidine nucleotides synthetized relative to the reserve pathway (uridine utilization) decreases in the series: kidneys greater than duodenum mucosa greater than lungs greater than liver greater than pancreas greater than bone marrow greater than brain greater than spleen. The results of 2-14C]orotic acid and 53H]uridine incorporation into UMP and CMP of the liver and spleen tissues RNA are interpreted in terms of the concept on existence of separate pools of pyrimidine phosphates--RNA precursors. |
